Center-punch.



Nea/"1783.749

PATBNTED FEB. 28, 1905. J'. J. HARTLEY @c J. M. STRYHAL.

CENTER PUNCH. APPLIUATIGN FILED APR. 26, 1904.

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diran STATES Patented February 28, 1905.

ATENT Ormea.

.hit/IES J. HARTLEY AND JOSEPH- M. SiRYH'AL, OF SCHEN ECTADY, NFA/VYORK, ASSIGNORS T0 BROWN & Sl-IARPE MANUFAClURlNG- CO., OF

IRUVIDENUE, RHODE ISLAND.

SPECIFICATION forming part of Letters Patent No, 783,749, dated February28, 1905.

Application tiled April 26, 1904. Serial No. 204.970.

Be it known that we, Janus J. HAR'rLnY and .losnrn M. STRYHAL, citizensoi' the United States, residing' at Schenectady, ,in the county ofSchenectady and State of New York, have invented a new and usefulImprovement in Center-Punches, of which the following` is aspeciiication.

This invention relates to improvements in punches, and refers moreparticularly to a centering' and prick punch `for machinists use inmakingl suitable indentations in metal preparatory to drilling' thesame.

The object oi' this device is to produce a neat and compact tool for thepurpose mentioned in which all ot' the elements necessary to produce thedesired indentation are conlined within a suitable handle or case andbrought into action automatically by the mere pressure or theprick-point upon the article to be indented.`

Anotlier object of the invention is to produce a center -punch operatedby a springiiiressure to indent the metal without the use oi' a hammeror other independent driving` device, whereby the indentation `formingthe center may be accurately located and impressed on the metal withoutany radial or lateral strain exerted on the punch.

Further objects will appear in the subsequent description.

ln the drawings, Figure l is an elevation oi" a tool embodying ourinvention. Figs. 2, 3, and 4 are vertical sectional views through thedevice seen in Fig'. l, showing' the operation and manner o't applyingthe same, the parts being' normal in Fig'. 2 and partially compressed inFig'. 3 and the striker-plunger as operated in Fig'. 4 to produce thedesired indentation. Figs. 5, 6, 7, 8, and 9 are detail views of thedetached parts ot' our invention.

Similar reference characters indicate corresponding' parts in all theviews.

Yln carrying' out the objects stated we provide a suitable case, whichnot only serves to inclose and guide the movable parts hereinafterdescribed, but also forms a handle by which these parts may be broughtinto action.

rlhis case is shown as consistin, 1;o'tl a slightlytapering' tubularbody 1, having a tubular tip or guide 2, secured to the lower part ofthe concentric tubular body, while the Lipper part is normally closed bya cap 3, also secured to the main body l. A punch-rod 4 is reciproeallymovable in the lower end of the case and extends above and beneath theopposite ends ot the section 2, in which it is guided, the lowerextremity being' tapered to a sharp point 5, which lies in the axis otthe punchrod and tubular bodyl and serves to produce the desiredindentation in a manner hereinafter described. The upper end of thispunchrod 4 is provided with an enlarged head 6, which is guided in acylindrical chamber 7 in the lower end of the tubular body l. lhe upperend of the tubular section 2 is provided with a bushing' 8, whichencircles the punchrod 4 and forms an additional guide 'for the said rodin its reciprocal movement, the bushing' being usually screwed into theupper end o't' the section Q, which latter is drawn in toform a guidefor the lower end ot' the punchrod. This rod 4 is provided withlaterally-projectingl shoulders 9, located between the bushingl 8 and anannular shoulder l0 at the base of the section 2, and between theshoulders El and bushing' 8 and encircling' therod 4 is a coil-spring'l1, which operates to lorce the punch-rod 4 f ,lownwardly, so that theshoulders 9 normally rest upon the shoulders l0, as seen in Fig. 2.

The head 6 of the punch-rod 4 is provided with a recess l2, Fig'. 9, inwhich is inserted one end ot' an upright pawl 1,3, rising' from the head6, the lower end o't' the pawl, which enters the recess, being reducedin width, so as to form lower and upper shoulders on the pawl whichengage the opposite faces of the head 6 to hold the pawl from endwisedisplacement and at the same time to permit the pawl to be movedpositively endwise by the movement oi" the punch-rod 4, it being'understood that although the pawl 13 is removable laterally Jfromengagement with the head when the parts seen in Fig'. 9 are detachedAfrom the main body l said pawl is held in its upright position fromlateral displacement by the adjacent side wall of the central body 1when the parts are assembled.

A plunger' or striker 14 is reciprocally movable in the upper end of themain body 1 and consists of a cylindrical body, of iron or equivalentmaterial, having a lengthwise groove 15 in one of its upright faces forreceiving a tripping' member 16, said g'roove being extended upwardlyfrom the lower face of the plunger or striker 14 and is also adapted toreceive the upper end of the pawl 13 when it is tripped'. rlhis pawl 13is provided with a tooth 17, which normally engages the lower face ofthe plunger or striker 14, which is undercut to form an engaging' tooth,and the pawl is held in this position by a spring 18, said pawl being'adapted to elevate the plunger or striker 14 against the action of aspring 19 when the point is engaged with the article to be indented andwhen the handle or case is depressed. The spring' 19 is arranged withinthe case and is interposed between the cap 3 and upper end of theplunger or striker 14,

so that when the plunger or striker is elevated against the action ofthe spring' in the act of making' an indentation in the article the trip16 automatically releases the tooth 17 of the pawl 13 from engagementwith the plunger or striker and the spring 19 instantly operates theplunger or striker downwardly with considerable force against the upperend of the punch-rod 4, thereby producing the desired indentation, whichindentation may be deepened by repeating' the operations just described,and the tension of the spring 19 may be varied by adjusting the cap 3.

The tripping member 16 is removably secured to the tubular body and isheld in place by a stud or pin 20, which enters an aperture 21 in theside wall of the inclosing' case, said stud being secured to thetripping-member and is simply inserted in the aperture to hold themember from endwise movement, it being' held from lateral movement bythe plunger or striker and adjacent wall of the case, between whichparts the said member is located.

In the operation of our invention the point 5 is tirst located at thedesired point upon the article to be indented, whereupon the device isbrought to an upright position and the operator engages the case orhandle and depresses the same, first against the action of the spring 11and then against the action of the spring 19, it being understood thatduring this depression of the case the tooth 17, which normally engagesthe lower edge of the plunger or striker, elevates said plunger orstriker a limited distance until the upper end of the pawl,whichprojects slightly beyond the tooth 17, eng'ag'es a cam-face 22 upon thelower end of the tripping member,whereupon the plunger is released andthe spring' 19 forces the plunger downwardly with considerable forceagainst the upper end of the punch-rod 4, and

thereby produces the desired indentation. The tooth 17 is located somedistance above the upper end of the punch-rod 4, and therefore permitsthe plunger to be moved through such distance by the action of thespring 19 before striking the upper end of the punch-rod. It is thusapparent that two forces are applied to make the indentation, one by thepressure of the operator upon the case or handle and the other by theinstantaneous blow produced by the plunger 14 and spring' 19.

The central tubular body 1 is provided with an inner annular shoulder23, which serves to limit the downward movement of the plunger, theshoulder 23 and the shoulder 17 of the pawl 13 being' so relativelyarranged that when the plunger is seated on the shoulder 23 the shoulder17 is in position to engage the plunger when the punch-rod is elevatedor, more properly, when the handle or case is depressed.

vHaving thus described our invention, we claim as new and desire tosecure by Letters Patent4 In a center-punch, comprising a tubular bodyhaving' a threaded upper end, and a cap screwed on said threaded end, atip removably secured to the lower end of said body,aspring pressedpunch-rod in said tip, a head on said rod extending into said body, saidhead being recessed with an upright pawl entering' said recess at itslower end, the upper end of the pawl bearing against the interior of thebody, a solid plunger of the same cross section throughout'arranged inthe body, a spring' seating directly upon the upper end of said plungerand bearing against the interior of the cap. said cap being concaved onits under face to form a seat for the spring' to retain the latter inposition, said plunger having' a lengthwise groove formed therein, atrip member arranged in said groove, said trip member formed of anelongated strip of material having' its lower end curved inwardly tobear against the bottom wall formed by the plunger-g'roove, saidthreaded portion of the body adjacent its lower end being formed with anaperture, a rivet extending through said aperture and secured to theupper end of said trip member, said plunger-groove receiving the Lipper'end of the said pawl when the latter is tripped, said inwardly-curvedlower end of the trip member forming a cam-face on its outer face, saidpawl having' an inwardly-extending' shoulder normally engaging' the saidplunger and retaining the latter in its upright position.

ln testimony whereof we have signed our names to this specification inthe presence of two subscribing' witnesses.

JAMES J. HARTLEY. JOSEPH M. S"RYHAL.

lfitnesses:

ALEX. F. MACDONALD, GnNnvinvn HAYNns.

